The full Mueller report should offer some information on how the Russia conspiracy theory started, but we'll likely need more investigation.

Special counsel Robert Mueller had become something of a messiah figure to the Trump haters. Like a god, he was remote, white-haired and reputed to work miracles. But Mueller ultimately disappointed his worshipers, establishing none of the Russian collusion they had been banking on to bolster their efforts to overturn the 2016 election.

The Russian collusion story had been an article of faith for the Resistance and the press. But why were so many people so deeply convinced of something that was not true? Who was behind not only concocting this fantastic tale but also embedding it in the highest levels of the Justice Department, the intelligence community and the news media?

This question had been on hold during the Mueller investigation. Government officials could not dig into it because anything they might do publicly would have been denounced as interference or “obstruction.” But with the Mueller phase concluded, the gates have opened.

President Trump retweeted a link about a Wall Street Journal op-ed saying the Obama administration must account for “abuse of surveillance powers.” “Time to investigate the Obama officials who concocted and spread the Russian conspiracy hoax!” Sen. Rand Paul, R-Ky., tweeted. Senate Judiciary Committee Chairman Lindsey Graham, R-S.C., called for the appointment of a new special counsel. And former George W. Bush administration spokesman Ari Fleischer asked what could be the ultimate question, “What did Barack Obama know and what and when did he authorize it?”

How Obama's team targeted Trump

The Russia investigation did not come from nothing, of course. Moscow did try to influence the 2016 election, part of a long history of attempted involvement in American politics going back to the days of the Comintern. This Russian activity prompted President Obama to tell Vladimir Putin personally to “cut it out” or face “serious consequences.” And the FBI gave the Trump campaign a standard counterintelligence briefing on the possibility of foreign interference in the summer of 2016, multiple government sources told NBC News and CNN.

Yet Obama officials also treated Trump campaign staffers as targets themselves. They used cooperative foreign intelligence services to chat them up overseas, both to put a layer of deniability between them and this questionable behavior, and to get around prohibitions against spying on American citizens. The recently released transcript of the House Committee on the Judiciary and Committee on Government Reform and Oversight interview with Trump campaign adviser George Papadopoulos goes into great detail how this targeting was conducted. Papadopoulos claims that foreign governments are now cooperating to reveal more about these activities.

There are also numerous classified documents related to the collusion illusion that have been either hidden or released in severely redacted form. Last September, President Trump instructed the Office of the Director of National Intelligence and the Department of Justice immediately to declassify materials related to the Russia investigation, including “all text messages … without redaction” of James Comey, Andrew McCabe, Peter Strzok, Lisa Page and Bruce Ohr, as well as documents concerning the warrant application under the Foreign Intelligence Surveillance Act for Trump adviser Carter Page.

Democrats objected that declassifying text messages regarding the Russia investigation will compromise FBI “sources and methods,” and the move was delayed after "key allies" objected.

Sources and methods must be known

However, sources and methods are the central question when it comes to investigating the investigators. So far as methods are concerned, what we know about them already are hardly worth being classified. They involve a basic counterintelligence technique, getting people to talk. In the Carter Page case, the target was a marginal character on the periphery of the 2016 Trump presidential campaign. This is not exactly on the level of the previously classified methods revealed by Edward Snowden.

But if there were some highly technical, super secret surveillance methods being used against others, including Trump himself, it is imperative that they be revealed. The notion that the U.S. government was ordered to use such advanced tools against a major party presidential campaign or a president himself is to say the least troubling, and potentially a criminal abuse of power.

Yet former National Intelligence Director James Clapper claims that the sketchy dossier was not the main source. OK then, what was? Settling this question publicly is more important than protecting any alleged source. The country was on the verge of a grave constitutional crisis that far outweighed this narrow, and perhaps nonexistent, protection rationale. It’s time to have cards on the table.

Many revelations from this investigation to date have given dramatic weight to the idea that the FBI and intelligence community were engaged in an effort to derail the 2016 Trump presidential campaign and later to use an “insurance policy” to subvert the Trump presidency. It is pointless to continue to argue about this in the dark. If there is evidence that supports the Democrats’ charges in these redacted documents, why not let the public know? Hiding behind “sources and methods” won’t cut it.

Trump should declassify these secrets

Last August, former CIA Director John Brennan on Meet the Press called President Trump’s behavior “treasonous, which is to betray one’s trust and to aiding and abet the enemy, and I stand very much by that claim.” Now he contritely admits that he might have relied on “bad information.” But Brennan was at the center of the collusion myth from the beginning. He had received “bad information” regarding Russian efforts to penetrate the Trump campaign from foreign intelligence sources dating back to 2015.

Early 2016, Brennan convened an interagency task force at Langley that included representatives from the CIA, the FBI, the Department of the Treasury, the Justice Department, the Office of the Director of National Intelligence and the National Security Agency. Obama administration officials compiled a list of the key classified documents from this investigation after the 2016 election out of fear that the incoming Trump team would destroy them, according to The New York Times. So where is this list and where are the documents? Who was involved in Brennan’s working group, and were any of them coordinating with the Clinton campaign?

President Trump already has the authority to declassify much of this hidden information. In the spring of 2017, when the president charged that former national security adviser Susan Rice’s “unmasking” of U.S. persons in intelligence products was potentially criminal, Rep. Adam Schiff, D-Calif., said, “If he’s going to make accusations of criminality against anyone, he needs to show evidence to support that kind of a charge.” Rep. Eric Swalwell, D-Calif., added that “if the president wants to say that Susan Rice committed a crime, he has the power to declassify. No one else does.”

Couldn’t agree more.

It is probable that the full Mueller report goes into some of these issues, but it is likely that more investigation will need to be done. Democrats calling for transparency should be careful what they wish for. We are looking at what might be an unprecedented level of government interference in the 2016 election that makes Watergate look like a third-rate burglary.

James S. Robbins, a member of USA TODAY's Board of Contributors and author of "Erasing America: Losing Our Future by Destroying Our Past," has taught at the National Defense University and the Marine Corps University and served as a special assistant in the office of the secretary of Defense in the George W. Bush administration. Follow him on Twitter: @James_Robbins